Fluid gauge



Sept. 15, 1936. a AFF ECK 2,054,579.

FLUID GAUGE Filed Sept. 9, 1955 WITNESSES Patented Sept. 15, was

FLUID GAUGE Gregor 8. Meek, Detroit, Mich. Application September a, mi, Serial No. cram 3Clnims.

The invention relates to fluid gauges of the type having a diaphragm chamber, the volume of :which is varied by the hydrostatic pressure oi a conflned body of liquid thereabove, the dia- '-5 phragm chamber being connected to a suitable indicator distant therefrom togauge the volume of liquid in the body. -An object of the invention is to provide a simple and durable gauge of this type which can be inexpensively manufactured and in which compensation for variations in temperature is efiected by the parts forming the diaphragm jchamber.

The invention further consists in the several features hereinafter described and claimed.

- In the accompanying drawing,

Fig. 1 is an elevation of a gauge embodying the invention as it appears when mounted in a tank, parts being broken away and parts being shown in section;

. Fig.2 is a sectional elevation of the diaphragm chamber;

Fig. 3 is a top plan view of a frame or spider for the diaphragm chamber, and

Fig. 4 is a detail view of one of the diaphragm disks or plates.

In this drawing, in designates a liquid receptacle, such as the gasoline tank of a motor-driven vehicle. A frame or spider ll of pressed sheet metal is mounted within the tank near the bottom thereof and has an annular body portion consisting of a flat top wall i2 with a depending marginal flange l3, there being a substantially circular opening H in the top wall. A plurality of spaced legs I! form downward extensions of the flange l3 and have out-tumed feet or lugs l6 whiclf'are spot-welded or otherwisesecured to the bottom wall of the tank.

Diaphragm disks or plates l1 and ll of thin flexible sheet metal are soldered to the upper and lower faces of the top wall l2 to form a shallow chamber l9 between them bounded at its periph =ery by the edge of the opening I. The assembly or casing thus formed is placed in a suitable mold and subjected to pressure to slightly bulge orcrown the disks l1 and I8 to a bowed shape, as seen in Fig. 2.

.The opening M in the spider top wall includes diametricallyopposite notches 20 and 2i, and ,the upper diaphragm disk I! is provided with small openings 22 and 28 to respectively register with these'notches. The disk I'I has an extension ortab 24 at which the opening 22 is located. 'The disk It is similar to the disk ll except that 55 the openings 22 and 23 are omitted. The opening 23 is closed after the device is assembled, as hereinafter described.

A flanged nipple 25 is secured, as by solder, to the upper disk H in register with the opening 22, and has secured therein the lower end of a bent u tube 28 of small internal diameter, the other end of which is secured in a nipple 21 passing through the'side wall of the tank. The reduced inner end of the nipple 21 is upset and soldered over a flange 28 riveted and soldered to the tank. A tube 29 of small internal diameter connects thenipple 21 with a suitable indicator 30, here shown to be a glass tube forming an indicating column. V

I The diaphragm chamber I9 and connected tubes are fllled with a suitable liquid, such as a light oil, through an opening in the nipple 21 subsequently closed by a screw 3|. During filling the vent opening 23 in the upper diaphragm disk I! is open, but after the filling operation it is covered by a drop of solder or otherwise closed.

The hydrostatic pressure of the liquid in the tank l0 acts to press the'diaphragm disks I1 and i8 inwardly and force indicating liquid out of the diaphragm chamber into the indicator 30, by way 5 of the connected tubing. The height of the liquid in the indicator is proportional to the height of the tank liquid above the diaphragm chamber, thereby making it possible to determine the volume of liquid in the tank.

It is necessary or desirable to have some means of compensating for the change in volume of the liquid in the diaphragm chamber and connected tubing over the original volume of the chamber and tubing with variations in temperature. This is accomplished by making the frame or spider I l and diaphragm disks l1 and I8 of materials having different coeflicients of thermal expansion.

A steel spider and brass diaphragm disks will efiect such compensation. The expansion of the 40 brass diaphragm disks by an increase in temperature is greater than that of the steel spider, with the result that the disks increase their convexity and also the volume of the chamber between them. Compensation is thus effected without requiring additional parts.

What I claim as new and desire to secure by Letters Patent is:

1. A fluid gauge, comprising a support having an opening, a pair 01' plates marginally attached to opposite sides of said support to form a liquid chamber with said opening, at least one of said plates forming a diaphragm displaceable by external fluid pressure to vary the volume of said chamber, and indicating means including a tube secured to the outer face of one of said plates at the stationary attached portion thereof and communicating with said chamber, the periphcry of said opening being notched to communicate with said tube.

2. A fluid gauge, comprising a support having an opening, a pair of diaphragms marginally secured on opposite sides of said support and forming a liquid chamber with said opening, said diaphragms being displaceable by external fluid pressure to vary the volume of said chamber, and indicating means responsive to changes in the volume of said chamber, said diaphragmshaving convex outer sides and having a greater temperature coemcient of expansion than said support to of thermal expansion to vary the volume 01' said chamber and thereby compensate for variations in temperature.

GREGOR S. AFFLECK. 

